Method and filling a polygon and recording medium

Abstract

For a polygon without self-intersection, with one of line segments constituting the outline of the polygon selected sequentially in the counterclockwise rotation, all the bits in the right direction of the selected line segment on the horizontal coordinate, inclusive of those for the selected line segment, on the plane work area (1 bit/pixel) of the work memory are inverted to draw (Step S 22 ). Subsequently, only some of the line segments constituting the outline of the polygon whose vectors are in the upward direction (which makes an upward vertical-coordinate variation) are further drawn on the work memory ( 2 A) (Step S 23 ). Finally, the drawing information is transferred with extension from the work memory to the display memory (Step S 24 ). Having the above steps, a method for achieving proper filling of a polygon with a decrease in load on a processor is provided.

I claim:  
     
       1. A method for filling a polygon, using an image processing system which has a work memory having a rectangular memory area of a plurality of bits, for storing information of one pixel by n (n≧1) bits and a display memory having a rectangular memory area of a plurality of bits, for storing information of one pixel by m (m>n) bits and displays an image based on said information stored in said display memory, to fill the inside of said polygon, said work memory being blank in an initial state, 
       said method comprising the steps of:  
       (a) obtaining outline information defining line segments constituting an outline of a polygon to be filled;  
       (b) performing bit inversion to make drawing of filled polygon through inverting all bits in a predetermined horizontal direction on a horizontal coordinate of said work memory corresponding to each of said line segments while selecting each of said line segments constituting said outline of said polygon to be filled in a predetermined rotation based on said outline information;  
       (c) further drawing said line segments constituting said outline of said polygon to be filled on said work memory where said drawing of filled polygon is performed based on said outline information; and  
       (d) transferring information stored in said work memory to said display memory after said step (c).  
     
     
       2. The method of claim  1 , wherein 
       said step (c) includes the step of drawing all said line segments constituting said outline of said polygon to be filled and selected in said predetermined rotation.  
     
     
       3. The method of claim  1 , wherein 
       said polygon to be filled includes a polygon without self-intersection,  
       said bit inversion in said step (b) includes one of a first inversion mode for inverting bits inclusive of those corresponding to said line segments on said work memory and a second inversion mode for inverting bits not inclusive of those corresponding to said line segments,  
       said step (c) includes the step of drawing only some of said line segments constituting said outline of said polygon to be filled and selected in said predetermined rotation whose vectors have a vertical variation in a predetermined vertical direction, said predetermined vertical direction being determined by said bit inversion, said predetermined rotation and said predetermined horizontal direction, in which some of said line segments which fail to be drawn, lacking, in said bit inversion of the step (b) have a vertical variation.  
     
     
       4. The method of claim  3 , wherein 
       said bit inversion includes said first inversion mode,  
       said predetermined rotation includes a counterclockwise rotation,  
       said predetermined horizontal direction includes a right direction, and  
       said predetermined vertical direction includes an upward direction.  
     
     
       5. The method of claim  3 , wherein 
       said bit inversion includes said first inversion mode,  
       said predetermined rotation includes a clockwise rotation,  
       said predetermined horizontal direction includes a right direction, and  
       said predetermined vertical direction includes a downward direction.  
     
     
       6. The method of claim  3 , wherein 
       said bit inversion includes said second inversion mode,  
       said predetermined rotation includes a counterclockwise rotation,  
       said predetermined horizontal direction includes a right direction, and  
       said predetermined vertical direction includes a downward direction.  
     
     
       7. The method of claim  3 , wherein 
       said bit inversion includes said second inversion mode,  
       said predetermined rotation includes a clockwise rotation,  
       said predetermined horizontal direction includes a right direction, and  
       said predetermined vertical direction includes an upward direction.  
     
     
       8. The method of claim  3 , wherein 
       said bit inversion includes said first inversion mode,  
       said predetermined rotation includes a counterclockwise rotation,  
       said predetermined horizontal direction includes a left direction, and  
       said predetermined vertical direction includes a downward direction.  
     
     
       9. The method of claim  3 , wherein 
       said bit inversion includes said first inversion mode,  
       said predetermined rotation includes a clockwise rotation,  
       said predetermined horizontal direction includes a left direction, and  
       said predetermined vertical direction includes an upward direction.  
     
     
       10. A computer-readable recording medium for recording a program by which a computer performs the method for filling a polygon in accordance with claim  1 . 
     
     
       11. A method for filling a polygon, using an image processing system which has a work memory having a rectangular memory area of a plurality of bits, for storing information of one pixel by n (n≧1) bits and a display memory having a rectangular memory area of a plurality of bits, for storing information of one pixel by m (m>n) bits and displays an image based on said information stored in said display memory, to fill the inside of said polygon, said work memory being blank in an initial state, 
       said method comprising the steps of:  
       (a) obtaining outline information defining line segments constituting an outline of a polygon without self-intersection to be filled; and  
       (b) performing bit inversion to make drawing of filled polygon through inverting all bits in a predetermined horizontal direction on a horizontal coordinate of said work memory corresponding to each of said line segments while selecting each of said line segments constituting said outline of said polygon to be filled in a predetermined rotation based on said outline information;  
       wherein said bit inversion includes one of a first inversion mode for inverting bits inclusive of those corresponding to said line segments on said work memory and a second inversion mode for inverting bits not inclusive of those corresponding to said line segments,  
       said method further comprising the steps of;  
       (c) transferring information stored in said work memory to said display memory after said step (b); and  
       (d) drawing only some of said line segments constituting said outline of said polygon to be filled and selected in said predetermined rotation whose vectors have a vertical variation in a predetermined vertical direction on said display memory based on said outline information after said step (c), said predetermined vertical direction being determined by said bit inversion, said predetermined rotation and said predetermined horizontal direction, in which some of said line segments which fail to be drawn, lacking, in said bit inversion of the step (b) have a vertical variation.  
     
     
       12. The method of claim  11 , wherein 
       said bit inversion includes said first inversion mode,  
       said predetermined rotation includes a counterclockwise rotation,  
       said predetermined horizontal direction includes a right direction, and  
       said predetermined vertical direction includes an upward direction.  
     
     
       13. The method of claim  11 , wherein 
       said bit inversion includes said first inversion mode,  
       said predetermined rotation includes a clockwise rotation,  
       said predetermined horizontal direction includes a right direction, and  
       said predetermined vertical direction includes a downward direction.  
     
     
       14. The method of claim  11 , wherein 
       said bit inversion includes said second inversion mode,  
       said predetermined rotation includes a counterclockwise rotation,  
       said predetermined horizontal direction includes a right direction, and  
       said predetermined vertical direction includes a downward direction.  
     
     
       15. The method of claim  11 , wherein 
       said bit inversion includes said second inversion mode,  
       said predetermined rotation includes a clockwise rotation,  
       said predetermined horizontal direction includes a right direction, and  
       said predetermined vertical direction includes an upward direction.  
     
     
       16. A computer-readable recording medium for recording a program by which a computer performs the method for filling a polygon in accordance with claim  11 . 
     
     
       17. A method for filling a polygon, using an image processing system which has a work memory having a rectangular memory area of a plurality of bits, for storing information of one pixel by n (n≧1) bits and a display memory having a rectangular memory area of a plurality of bits, for storing information of one pixel by m (m>n) bits and displays an image based on said information stored in said display memory, to fill the inside of said polygon, said work memory being blank in an initial state, 
       said method comprising the steps of:  
       (a) obtaining outline information defining line segments constituting an outline of a polygon without self-intersection to be filled;  
       (b) performing bit inversion to make drawing of filled polygon through inverting all bits in a predetermined horizontal direction on a horizontal coordinate of said work memory corresponding to each of said line segments while selecting each of said line segments constituting said outline of said polygon to be filled in a predetermined rotation based on said outline information;  
       (c) transferring information stored in said work memory to said display memory after said step (b),  
       wherein said bit inversion includes a first inversion mode for inverting bits inclusive of those corresponding to said line segments on said work memory and a second inversion mode for inverting bits not inclusive of those corresponding to said line segments, and some of said line segment constituting said outline of said polygon to be filled and selected in said predetermined rotation whose vectors have a vertical variation in a first vertical direction are subjected to said bit inversion in said first inversion mode and some whose vectors have a vertical variation in a second vertical direction are subjected to said bit inversion in said second inversion mode, said first and second vertical directions being determined by said predetermined rotation and said predetermined horizontal direction so that said some of said line segments whose vectors have a vertical variation in said first vertical direction can be drawn with no lack when said bit inversion is performed in said first inversion mode and said some of said line segments whose vectors have a vertical variation in said second vertical direction can be drawn with no lack when said bit inversion is performed in said second inversion mode.  
     
     
       18. The method of claim  17 , wherein 
       said predetermined rotation includes a counterclockwise rotation,  
       said predetermined horizontal direction includes a right direction,  
       said first predetermined vertical direction includes a downward direction, and  
       said second predetermined vertical direction includes an upward direction.  
     
     
       19. The method of claim  17 , wherein 
       said predetermined rotation includes a clockwise rotation,  
       said predetermined horizontal direction includes a right direction,  
       said first predetermined vertical direction includes an upward direction, and  
       said second predetermined vertical direction includes a downward direction.  
     
     
       20. A computer-readable recording medium for recording a program by which a computer performs the method for filling a polygon in accordance with claim  17 .